The Cosmological Constant Problem and Running Vacuum in the Expanding Universe

Abstract

It is well-known that quantum field theory (QFT) induces a huge value of the cosmological constant, $\Lambda$, which is outrageously inconsistent with cosmological observations. We review here some aspects of this fundamental theoretical conundrum (`the cosmological constant problem') and strongly argue in favor of the possibility that the cosmic vacuum density ${\rho }_{\mathrm{vac}}$ may be mildly evolving with the expansion rate $H$. Such a `running vacuum model' (RVM) proposal predicts an effective dynamical dark energy without postulating new ad hoc fields (quintessence and the like). Using the method of adiabatic renormalization within QFT in curved spacetime we find that ${\rho }_{\mathrm{vac}}(H)$ acquires a dynamical component $\mathcal{O}(H^2)$ caused by the quantum matter effects. There are also $\mathcal{O}(H^n)$ ($n=4,6,..$) contributions, some of which may trigger inflation in the early universe. Remarkably, the evolution of the adiabatically renormalized ${\rho }_{\mathrm{vac}}(H)$ is not affected by dangerous terms proportional to the quartic power of the masses ($\sim m^4$) of the fields. Traditionally, these terms have been the main source of trouble as they are responsible for the extreme fine tuning feature of the cosmological constant problem. In the context under study, however, the late time ${\rho }_{\mathrm{vac}}(H)$ around $H_0$ is given by a dominant term (${\rho }_{\mathrm{vac}}^0$) plus the aforementioned mild dynamical component $\propto \nu (H^2-H_0^2)$ (with $|\nu |\ll 1$), which makes the RVM to mimic quintessence. Finally, on the phenomenological side we show that the RVM may be instrumental in alleviating some of the most challenging problems (so-called `tensions') afflicting nowadays the observational consistency of the `concordance' $\Lambda$CDM model, such as the $H_0$ and ${\sigma }_8$ tensions.

Matches the published version in Phil.Trans.Roy.Soc.Lond.A (2022)

References in corpus (37)

• Dynamics of dark energy
• Cosmology and the Fate of Dilatation Symmetry
• In the Realm of the Hubble tension $-$ a Review of Solutions
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Measurements of the Hubble Constant: Tensions in Perspective
• Cosmology Intertwined II: The Hubble Constant Tension
• Cosmology Intertwined III: $f{\sigma }_8$ and $S_8$
• Indications of a late-time interaction in the dark sector
• To H0 or not to H0?
• Dark energy: a quantum fossil from the inflationary Universe?
• Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study
• Cosmological Particle Production: A Review
• LXCDM: a cosmon model solution to the cosmological coincidence problem?
• Running vacuum against the $H_0$ and ${\sigma }_8$ tensions
• Renormalizing the vacuum energy in cosmological spacetime: implications for the cosmological constant problem
• Hubble expansion and structure formation in the "running FLRW model" of the cosmic evolution
• The $\bar{\Lambda }CDM$ cosmology: from inflation to dark energy through running $\Lambda$
• Running vacuum in quantum field theory in curved spacetime: renormalizing ${\rho }_{vac}$ without $\sim m^4$ terms
• Zero-point quantum fluctuations and dark energy
• Vacuum models with a linear and a quadratic term in H: structure formation and number counts analysis
• Relaxing the ${\sigma }_8$-tension through running vacuum in the Universe
• The Road to Precision Cosmology
• Cosmological constant vis-a-vis dynamical vacuum: bold challenging the $\Lambda$CDM
• Stringy-Running-Vacuum-Model Inflation: from primordial Gravitational Waves and stiff Axion Matter to Dynamical Dark Energy
• Inflationary physics and transplanckian conjecture in the Stringy Running-Vacuum-Model: from the phantom vacuum to the true vacuum
• Cosmographic approach to Running Vacuum dark energy models: new constraints using BAOs and Hubble diagrams at higher redshifts
• The Cosmic Coincidence as a Temporal Selection Effect Produced by the Age Distribution of Terrestrial Planets in the Universe
• Vacuum energy and cosmological evolution
• Torsion in string-inspired cosmologies and the universe dark sector
• Vacuum fluctuations in a supersymmetric model in FRW spacetime
• Do we Come from a Quantum Anomaly?
• From de Sitter to de Sitter: A non-singular inflationary universe driven by vacuum
• Geometrical origins of the Universe dark sector: string-inspired torsion and anomalies as seeds for inflation and dark matter
• Vacuum energy in Quantum Field Theory and Cosmology
• Running gravitational couplings, decoupling, and curved spacetime renormalization
• Renormalization, running couplings and decoupling for the Yukawa model in curved spacetime
• Implications of Dynamical Dark Energy in the expansion of the Universe and the Structure Formation

Cited by in corpus (51)

• Challenges for $\Lambda$CDM: An update
• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Renormalizing the vacuum energy in cosmological spacetime: implications for the cosmological constant problem
• An overview of what current data can (and cannot yet) say about evolving dark energy
• Running vacuum in the Universe: phenomenological status in light of the latest observations, and its impact on the ${\sigma }_8$ and $H_0$ tensions
• Negative cosmological constant in the dark energy sector: tests from JWST photometric and spectroscopic observations of high-redshift galaxies
• Coupled and uncoupled early dark energy, massive neutrinos and the cosmological tensions
• Equation of state of the running vacuum
• Phantom matter: a challenging solution to the cosmological tensions
• Composite Dark Energy and the Cosmological Tensions
• Alleviating the cosmological constant problem from particle production
• An Effective Sign Switching Dark Energy: Lotka-Volterra Model of Two Interacting Fluids
• A comprehensive numerical study on four categories of holographic dark energy models
• Gravitational Vacuum Condensate Stars
• ${\Lambda }_{\mathrm{s}}$CDM cosmology: Alleviating major cosmological tensions by predicting standard neutrino properties
• Observational Constraints on Dynamical Dark Energy Models
• Alleviating $H_0$ Tension with New Gravitational Scalar Tensor Theories
• Stringy Running Vacuum Model and current Tensions in Cosmology
• The Effective Theory of Gravity and Dynamical Vacuum Energy
• Running vacuum in Brans-Dicke theory: a possible cure for the ${\sigma }_8$ and $H_0$ tensions
• Anisotropic f(Q) gravity model with bulk viscosity
• Interacting dark energy after DESI DR2: a challenge for $\Lambda$CDM paradigm?
• Hubble tension in a nonminimally coupled curvature-matter gravity model
• Observational constraints on interacting vacuum energy with linear interactions
• Torsion at different scales: from materials to the Universe
• Dynamical systems of cosmological models for different possibilities of $G$ and ${\rho }_{\Lambda }$
• Cosmological constraints on time-varying cosmological terms: A study of FLRW universe models with $\Lambda (t)$CDM cosmology
• Solar chameleons: Novel channels
• Is cosmological data suggesting a nonminimal coupling between matter and gravity?
• Dark energy reconstruction analysis with artificial neural networks: Application on simulated Supernova Ia data from Rubin Observatory
• Imprints of screened dark energy on nonlocal quantum correlations
• Nonminimal global monopole
• Exploring Alternative Cosmologies with the LSST: Simulated Forecasts and Current Observational Constraints
• Effective approach to the Antoniadis-Mottola model: quantum decoupling of the higher derivative terms
• Litmus tests of the flat $\Lambda$CDM model and model-independent measurement of $H_0{r}_{\mathrm{d}}$ with LSST and DESI
• Beyond $\Lambda$CDM: Exploring a Dynamical Cosmological Constant Framework Consistent with Late-Time Observations
• Mass Modeling and Kinematics of Galaxy Clusters in Modified Gravity
• Quantum-Ordering Ambiguities in Weak Chern-Simons 4D Gravity and Metastability of the Condensate-Induced Inflation
• Running vacuum and H^4-inflation
• Equivalence of Dark Energy Models: A Theoretical and Bayesian Perspective
• Physical scale adiabatic regularization in cosmological spacetimes
• Phenomenological footprints of Lambda varying gravity theories inspired from quantum gravity models in the multi-messenger era
• Induced energy-momentum tensor in de Sitter scalar QED and its implication for induced current
• Dark energy from a geometrical gauge scalar-tensor theory of gravity
• Antimatter Gravity Experiments, the Astronomical Challenges to Lambda-CDM Cosmology and the Quantum Vacuum as a Possible Source of Gravity in the Universe
• Comment on the cosmological constant for $\lambda {\varphi }^4$ theory in $d$ spacetime dimensions
• Running Einstein Constant and a Possible Vacuum State of the Universe
• The stability of the de-Sitter universe in nonlocal gravity
• Tracing Signatures of Modified Gravity in Redshift-Space Galaxy Bispectrum Multipoles: Prospects for Euclid
• The Hubble tension as an effect of the renormalization of fundamental constants and cosmological parameters
• Dynamical-System analysis of single-axion monodromy inflation with periodically-modulated potentials